Air barrier



March 1962 F. A. KRAMER, JR 3,0 3, 8

AIR BARRIER Filed y 16, 1958 ATTORNEYS United States Patent 3,023,688 AIR BARRIER Fred A. Kramer, In, 1334 I McCutcheon, Brentwood 17, Mo. Filed May 16, 1958, Ser. No. 735,898 13 Claims. (Cl. 98-36) This invention relates to a new and improved apparatus for and a method of providing air barrier or a wall of air for use for example at the entrance to a building. The purpose of an air barrier is to confine an air space behind an opening so as to maintain a temperature within the confined air space and to keep insects and dust and wind out of the confined air space without resorting to any solid closure means.

According to the air barrier apparatus and systems of the prior art, a stream of air is directed downwardly from above the building entrance or the opening behind which the air space is to be confined. In the more efllcient systems, the air stream is caught in a pit below the entrance and recirculated. The fact that a pit is required to be built in the fioor of the entrance makes this system far too expensive to be practical for most applications. There are some systems of the prior art which require no pits but they are hopelessly inefficient. In one such system the air stream is directed downwardly from over the entrance or opening and the air is drafted from the sides at the bottom of the opening. Such a system is ineffective at performing the primary function of the air barrier, namely, confining the air space behind the opening. This system of the prior art fails to keep dust, insects, or wind out of the air space supposedly isolated behind the opening and also fails to efficiently maintain any temperature within the air space. In other Words, it is not much better than an open window.

Another system of the prior art merely directs a stream of air downwardly and outwardly from above the opening or entrance and makes no provision for recirculating the downwardly directed air stream. Such a stream requires a high velocity to be effective and is therefore uncomfortable for passage through the wall of air. Also, in order for the air stream to effectively maintain a temperature differential, the air stream must be heated and all of this heat is wasted since the air stream is not recirculated. Therefore, the system requires a lot of energy for heating the non-recirculated air. Lastly, the requirement of new air for the air stream means that more filtering is required of the incoming air for use in the air stream.

The present invention provides a system and method of providing an air barrier or wall which requires no pit yet is just as efficient as the above described system using a pit for recirculation. Because the system of the present invention requires no pit, the cost of the system is about one fifth of the cost of the pit system of the prior art. As a result, the system and method of the present invention is commercially practical whereas the cost of the pit system of the prior art is so high, its adoption by industry is very limited.

Briefly, according to the present invention, two separated streams of air are directed downwardly from above the opening. The air is withdrawn from between the two streams of air and recirculated. This action causes the two air streams to converge and form an air pocket which effectively seals off the air space behind the opening.

Further objects and advantages of the invention will become readily apparent as the following description of the preferred embodiment unfolds and when taken in conjunction with the drawings in which:

FIGURE 1 illustrates the apparatus of the present invention mounted in the doorway of a commercial establishment;

FIGURE 2 illustrates the operation of the invention;

FIGURE 3 is a more detailed showing of the apparatus of the invention.

As shown in FIGURE 1 the apparatus used in the preferred embodiment uses two sets of blowers 1'1 and 12. The blowers '11 exhaust into the casing 16. The blowers 12 exhaust into a casing 17. A cover plate or frame 25 joins the two casings 16 and 17 together and also form a top cover for the casings 16 and 17. An air filter 14 is mounted between the casings 16 and 17. The whole apparatus is hung above the doorway or entrance of a commercial establishment by the hanging rods 13 which are attached to the casings 16 and 17. The doorway is bounded on each side by walls 18 which are shown as glass for display purposes.

As shown in FIGURE 3 the blowers 11 are suspended by straps 26 from the plate 25 and exhaust into the casing 16 through an air passage bounded by walls 15. Inside the casing 16 are guide vanes 19 which extend throughout the length of the casing 16. These guide vanes serve to direct downwardly the air entering the casing 16 from the blowers 1 1. Mounted in the casing 16 below the guide vanes 19 is a heating coil 20 which extends throughout the length of the casing 16. The louvers 21 also extend from one end of the casing to the other and form elongated nozzles, which are directed generally downward. The louvers 21 may be turned to control the direction of the nozzles. The air from the blowers, after being directed downwardly by the guide vanes 19, passes through the heating coil 26 where the air is heated. After passing through the heating coil 29, the air is forced through the longitudinal nozzles formed by the louvers to form a downwardly directed stream of air below the nozzles. The casing 17 also contains guide vanes, a heating coil, and louvers and it is constructed just like the casing 16. The blowers 12 exhaust into the casing 17 and a downwardly directed stream of air is formed below the casing 17.

In FIGURE 2, the reference number 22 designates generally the air stream formed below the casing 16. The reference numeral 23 designates generally the air stream formed by the nozzles in the casing 17. The blowers 11 and 12 withdraw air from above the filter 14 and feed it into the casings 16 and 17 The pressure in the casings 16 and 17 forces the air out of the nozzles in the casings to form the air streams 22 and 23. The air streams from the nozzles proceed down to the floor of the doorway. Because the air is withdrawn by the blowers from between the two streams of air a slightly lower pressure will exist between the two streams than exists outside of the two streams. This pressure difference will cause both streams 22 and 23 to be deflected inwardly upon reaching the floor. A generally upward low velocity flow will exist between the two streams. This upward flow passes through the filter 14 to be recirculated by the system. Thus, the two air streams form a pocket between them from which the air is withdrawn for recirculation. These two streams of air, together with the pocket formed be tween them, form an efiicient air barrier effectively sealing oh the air space behind the air barrier from the out side Instead of being used in a doorway the applicants invention of course could be used in combination with a window, skylight, or any other type of opening. Another way the applicants invention could be used is to define the walls of a room. One stream of air could form one wall of a small room and the other stream of air could be used to form another wall of the room. For example, in FIGURE 1, the walls 18 could be two walls of a small room and the two streams formed from the nozzles in the casings 16 or 17 could be the other walls of a small room. Alternatively, all of the walls of the room could be formed by streams of air, with air being withdrawn from within the streams and recirculated.

Although it is preferable in doorways that the air streams be downwardly directed, this is not absolutely essential, and would not be necessary at all in windows or in skylight. In high doors it may be desirable to have the air streams directed horizontally to decrease the distance that the air streams have to travel. One single blower could be used to supply the air pressure to both of the casings instead of a plurality of blowers as described and shown in the preferred embodiment. These and other modifications come within the spirit and scope of the present invention which is to be limited only as defined in the appended claims.

What is claimed is:

1. In combination, means defining a building doorway comprising two vertical parallel walls facing each other, a fioor and a ceiling; a first casing mounted in said doorway positioned at the top of said doorway suspended from said ceiling, the length of said first casing extending the width of said doorway, said first casing having first means defining at least one elongated first nozzle extending the length of said first casing and directed towards said floor, a first heating coil mounted in said first casing above said first nozzle, said first heating coil being positioned in a horizontal plane and extending the length and depth of said casing, a second casing mounted in said doorway positioned at the top of said doorway suspended from said ceiling, the length of said second casing extending the width of said doorway, said second casing being spaced from said first casing, said second casing having second means defining at least one elongated second nozzle extending the length of said second casing and directed towards said floor, a second heating coil mounted in said second casing above said second nozzle, said second heating coil being positioned in a horizontal plane and extending the length and depth of said second casing, at least one first blower mounted between said first and second casings withdrawing air from between said casings and exhausting air into said first casing, at least one second blower mounted between said casings withdrawing air from between said casings and exhausting air into said second casing, a first set of guide vanes mounted in said first casing positioned to deflect air entering said first casing from said first blower toward said first nozzle, a second set of guide vanes mounted in said second casing positioned to deflect air entering said second casing from said second blower toward said second nozzle, and an air filter mounted between said casings below said first and second blowers.

2. In combination, a wall having an opening defined therein, a first casing mounted in said opening and positioned at one side of said opening, said first casing having first nozzle means defined in the Wall of said casing extending across the width of said opening and directed towards the opposite side of said opening, a second casing mounted in said opening and positioned at said one side of said opening, said second casing having second nozzle means defined in the wall of said second casing extending across the width of said opening and directed towards said opposite side of said opening, said second nozzle means being spaced from said first nozzle means in a direction going through said opening, and means to withdraw air from between said first and second nozzle means and exhausting the withdrawn air into said first and second casings.

3. An apparatus for providing an air barrier when mounted in an opening comprising a frame, a first casing mounted on said frame, a first nozzle means defined in the wall of said first casing, a second casing mounted on said frame, a second nozzle means defined in the wall of said second casing, said second nozzle means being directed generally in the same direction as said first nozzle means, said second nozzle means being spaced from said first nozzle means, and means to withdraw air from between said first and second nozzle means and to exhaust the withdrawn air into said first and second casings.

4. In combination, means defining a building doorway, first means for producing a first air stream across the width of said doorway downwardly directed from the top of said doorway, second means for producing a second air stream across the width of said doorway downwardly directed from top of said doorway spaced from said first air stream and means for withdrawing air from between said two air streams and supplying it to said first and second means for recirculation in said first and second air streams.

5. In combination, a wall having an opening defined therein, first means for producing a first air stream across the width of said opening directed from one side of said opening to the other second means for producing a second air stream across the width of said opening directed in the same direction as said first air stream but spaced from said first air stream in a direction going through said opening and means for withdrawing air from between said two air streams and supplying it to said first and second means for recirculation in said first and second air streams.

6. In combination, means defining a building doorway, first means for producing a first air stream across the width of said doorway downwardly directed from the top of said doorway, second means for producing a second air stream across the width of said doorway downwarclly directed from the top of said doorway spaced from said first air stream in a direction going through said doorway and means for withdrawing air from between said two air streams, the spacing between said air streams being large enough so that the air streams do not flow together before reaching the bottom of said doorway.

7. A mehtod of isolating an air space behind a doorway comprising the steps of forming a first stream of air within said doorway directed downwardly from the top of said doorway and extending across the width of said doorway, forming a second stream of air within said doorway directed downwardly from the top of said doorway and extending across the width of said doorway, spacing said second stream of air from said first stream of air in a direction going through said doorway, Withdrawing air from between said first and second streams of air, and recirculating the air withdrawn in said step of withdrawing air in said first and second streams of air.

8. A method of isolating an air space behind an opening defined in a wall comprising the steps of forming a first stream of air within said opening directed from one side of said opening to the other and extending across the width of said opening, forming a second stream of air within said opening directed in the same direction as said first stream and extending across the width of said opening, spacing said second stream of air from said first stream of air in a direction going through said opening, withdrawing air from between said first and second streams of air, and recirculating the air withdrawn in said step of withdrawing air in said first and second streams of arr.

9. A method of isolating an airspace behind a doorway comprising the steps of forming a first stream of air within said doorway downwardly directed from the top of said doorway and extending across the width of said doorway, forming a second stream of air within said doorway downwardly directed from the top of said doorway and extending across the width of said doorway, withdrawing air from between said first and second air streams, and spacing said second air stream in a direction going through said doorway sufiiciently from said first air stream that said first and second air streams do not combine before reaching the bottom of said doorway.

10. A method of isolating an air space behind a doorway comprising the steps of forming a first stream of air within said doorway directed downwardly from the top of said doorway and extending across the width of said doorway, forming a second stream of air within said doorway directed downwardly from the top of said doorway and extending across the width of said doorway, spacing said second stream of air from said first stream of air in a direction going through said doorway, and withdrawing air from between said first and second streams of air.

11. In combination, means defining a building doorway, first means for producing a first air stream across the width of said doorway downwardly directed from the top of said doorway, second means for producing a second air stream across the width of said doorway downwardly directed from the top of said doorway spaced from said first air stream, and means for withdrawing air from between said two air streams.

12. An air barrier device comprising a first wall means and second wall means facing said first wall means, a third wall means extending from said first wall means to said second wall means, a fourth wall means facing said third wall means and extending from said first wall means to said second wall means, means to produce a first stream of air directed from said first wall means toward said second wall means and extending from said third wall means to said fourth wall means, second means to produce a second stream directed from said first wall means toward said second wall means and extending from said third wall means to said fourth wall means, said second means being positioned so that said second stream of air is spaced from said first stream of air in a direction generally parallel to said first, second, third and fourth wall means and means for withdrawing air from between said first and second streams.

13. An air barrier device comprising a first wall means, a second wall means facing said first wall means, means for producing a first air stream directed from said first wall means toward said second wall means, means for producing a second air stream spaced from said first air stream and directed from said first wall means toward said second wall means, means for withdrawing air from between said first and second air streams and recirculating the withdrawn air in said first and second air streams.

References Cited in the file of this patent UNITED STATES PATENTS 983,877 Cummings Feb. 14, 1911 1,279,993 Cummings Sept. 24, 1918 1,750,794 Cutler Mar. 18, 1930 2,565,933 Schneible Aug. 28, 1951 2,593,702 Schneible Apr. 22, 1952 2,863,373 Steiner Dec. 9, 1958 FOREIGN PATENTS 307,257 Switzerland Aug. 1, 1955 

